Folding leg mechanism



June 2, 1959 L'J. FERDINAND ET AL 2,889,186

FOLDING LEG MECHANISM Filed Sept. 20, 1957 INVENTORS:

IRWIN J. FERDINAND RAI EI-I J. B LLON 47 TTI'Y FOLDING LEG MECHANISM Irwin J. Ferdinand, Glencoe, and Ralph J. Bellon, Gten view, 111., assignors to A. Hirsh Mfg. (10., Skotrie, 111., a corporation of Illinois Arrlisafim eptem er 1.957rSerial 685,159

4 Claims. (Cl. 311-99 This invention relates to a folding leg mechanism, and more especially to a folding leg selectively movable between a depending, table-supporting position, and an upper folded position in which it is disposed beneath and in adjacent relation with the undersurface of the table top. This folding leg mechanism has utility, for example, in substantially all table environments where foldable legs therefor are desired, such as table tennis tables, other game tables including those which may be relatively heavy (as pool tables), banquet tables, etc.

Tables equipped with foldable legs are known in the art, and many different leg structures have been proposed to meet the inherent objections of instability, complexity, and functional awkwardness thereof. However, so far as is known, no leg has heretofore been developed which satisfies all of these difiiculties, and most do not offer a satisfactory solution for'even one thereof. It is, accordingly, an object of this invention to provide a leg structure that overcomes such disadvantages in the prior art structures.

Another object of the invention is that of providing a foldable leg adapted for use with tables and the like, which is movable from a collapsed or folded'position underlying the table top to a support position depending therefrom, and is automatically locked in the support position when moved thereinto. Another object of the inven tion is in the provision of a leg structure of the character described, which defines an angular orientation, when extended, with an axis normal to the table and diverges downwardly and outwardly therefrom, whereby the weight of the table enforces movement of the leg into its locked position, with the result that stability is always assured.

Still another object is to provide a foldable leg structure as described, wherein an upper edge portion of theleg substantially abuts the undersurface of a table top when the leg is in its supporting position so that greater stability is achieved because of the rigid constraint imposed on the leg by the table top. A further object of the invention is that of providing an interlock eflective between the table andleg for constraining the leg in a supportposition, and in which means are provided to compensate for normal wear of the interlocking components so that a firm, positive, interlock is always attained even after long periods of use of the leg structure.

Still a further object of the invention is in providing a folding leg made of relatively thin material such as sheet metal, but which is configurated and braced in a manner such thatthe leg is extremely strong and effectively resists transverse and longitudinal stresses applied thereto, as well as torsional stresses resulting from the angular orientation thereof when in the supporting position. Yet a further object is to provide aleg as described, wherein the relatively movable components of the. interlocking mechanism are guided with respect to each other when the leg articulates between the closed and open positions, to assure proper engagement of the components and to 2,889,186 Fatented sta e 2, 1959 2 avoid misalignment thereof. Additional objects and advantages of the invention will become apparent as the specification develops. i

An embodiment of the invention is illustrated in the accompanying drawing, in which- Figure 1 is a perspective view of a ping-pong table in its folded position; Figure 4 is a transverse sectional view taken along the line 4 1 of Figure 2; and Figure 5 is a greatly enlarged, perspective view showing one of the locking components employed in the leg mechanism.

The table illustrated inFigure l, and which is denotedin general with the number 10, is intended to be exemplary of tables with which the folding leg may be used. The table 10 has a planar top 11 which is formed in two sections of equal dimensions that abut each other along the center line 12. A table tennis net 13 extends trans versely across the top 11 above and in substantial alignment with the line 12. The table is seen to have a plu rality of legs 14 extending downwardly therefrom, and

there are eight in the specific illustration. The legsl i ate all identical, and for this reason only one will be de-.

scribed in detail hereinafter. It will be noted that the legs extend downwardly and outwardly at the four corners of each of the table sections, and the line along which each leg extends substantially bisects the respective corners.-

Referring now to Figures 2 and 3 in particular, it will be seen that each of the leg mechanisms 14 comprises a bracket 15 having a modified Y-shape, rigidly secured to the table top 11 by screws 16or other suitable means. The generally Y-shaped bracket 15 is defined by two sections or arms 17 and 18 which reversely correspond to each other. The sections each have a depending wall, denoted for identification with the numerals 19. and 20, and laterally extending flanges 21 and 22 respectively formed integrally therewith. The flanges 21 and 22 are apertured so as to' permit the screws 16 to pass therethrough.

The bracket sections 17 and 18 may be stamped from metal blanks and bent into the configurations shown in Figures 2 and 3, which are of stepped character. That is to say, the innermost extremities thereof withreference to the corner of the table top sections, are widelyspaced from each other and merge with inwardly turned portions that converge, and are then bent outwardly andextend in substantially parallel relation with the inner extremities to define the tail of the bracket. To facilitate the descrip;

with cars 28 and 29 pivotally mounted upon pins '30 and 31, respectively, extending through the walls 19 and 2 0 of the bracketsections. The'pins 30 and 31 define a pivotal supportfor the leg 27, and permit it to swing or articulate between the extended, depending position shown in Figure 2 and the folded. or collapsed position shown in Figure 3. As is seen mostclearly in Figure 4, the leg 27 has three integrally formed walls 32, 33 and 34, each of which is generally planar. The walls 32. and 34 diverge from the wall 33 and terminate in rounded edges 35 and 36, respectively.

lnterposed between the walls '32 and 34, intermediate the edges thereof and extending in generally parallel relation with the wall 33, is a support or reinforcing wall 37 having laterally turned flanges 38 and 39 that are contiguous with the respective walls 32 and 34 and are rigidly secured thereto, such as by spot welds at spaced intervals therealong. The wall 37 serves as both a compression and tension member in the sense that it prevents spreading of the walls 32 and 34, and also resists any compressive forces applied thereacross. As is apparent from Figures l and 2, the legs 27 taper downwardly and have a reduced cross section at the floor-engaging ends thereof.

The outer Wall 33 is provided with an elongated slot 40 adjacent its upper end that extends along the longitudinal axis thereof. Welded or otherwise rigidly secured to the wall 33 along the inner surface thereof is a reinforcing plate 41 contiguous therewith, that is provided with a slot extending along the slot 40 in alignment therewith. The plate 41 is equipped, adjacent the lower end of the slot 40, with a latch pin 42 that preferably has a rounded cross section throughout the central portion thereof which traverses the slot 40 and may have flattened end portions, as shown in Figure 4, which are welded or otherwise affixed to the plate.

The latch member 42 is adapted to seat within a recess 43 formed adjacent an end of a locking strut or latch 44 mounted upon a pivot 45 between the adjacent, facing tails 23 and 24 through which the pivot extends. As shown in Figure 5, the latch 44 has an aperture 46 therethrough that receives the pivot 45. The end of the latch 44 adjacent the recess 43 is equipped with a laterally turned lug 47 that is disposed intermediate the edges of the latch and rides along the plate 41 during movement of the leg 27 in a manner to be described hereinafter. The opposite end of the latch is turned upon itself, as shown at 48, to form a seat for a helical spring 49 having a hook 50 at one end extending through an aperture therefor in the seat, and which at its other end is equipped again with a similar hook that extends through an aperture 51 therefor formed in the tail 24 of the bracket section 18.

The recess 43 defines a seat for the latch pin 42, and tapers inwardly from a dimension at the outer edge thereof which is only slightly greater than the thickness of the latch pin 42 so as to snugly receive the same therein. At its inner end, the slot has a dimension slightly less than the thickness of the pin 42; and consequently, as the walls of the recess and/or of the latch pin 42 wear through repeated seating of the pin in the recess, the latch pin simply enters the recess to a greater extent until it is snugly received thereby. Thus, the latch pin is always snugly engaged by the walls of the recess since the spring 49 biases the latch 44 in a counter-clockwise direction about the pivot 45, thereby tending to seat the latch pin as deeply as possible in the recess 43.

The slot 40 at the open end thereof has outwardly diverging edges 52 and 53, defining a mouth therefor, which tend to cam or guide the latch 44 into the slot 40 in the event that it is removed or partially removed therefrom. It may be mentioned that the ears 28 and 29 of the leg 27 are formed integrally, respectively, with the walls 34 and 32 thereof. Also, the walls 19 and 20 to which the ears are pivotally secured, are cut away as shown at 54. The cut away or removed areas 54 extend into the adjacent areas of the inclined and tail portions of the bracket sections, and serve as a safety device to prevent pinching of the fingers by the latch 44 when it is released from the pin 42 and the leg 27 is swung upwardly.

In describing the functioning of the leg structure, consider initially the position thereof illustrated in Figure 3 wherein the leg is collapsed and extends along the undersurface of the table top 11. It will be assumed, of course, that the mechanism has first been mounted under the table top so that the longitudinal edges of the leg struc- 4 tureand particularly the leg 27 thereof--substantially bisect the adjacent table corner. It may be mentioned that any suitable means can be employed for constraining the leg 27 in its collapsed position, such as straps, hooks, etc., none of which are shown since they may be completely conventional and form no part of this invention.

As the leg 27 is swung downwardly, the latch 44 is guided within the slot 40 since it cannot fall through because of the stop action afforded by the lug 47 in its abutment with the plate 41. The latch will not move upwardly, or in a counter-clockwise direction about its piovt 45, because of the gravitational force acting thereon, and further because of the biasing force exerted by the spring 49 which tends to constantly rotate the latch. in a clockwise direction about the pivot 45. The inclined edges 52 and 53 which define the mouth of the slot 46, serve the dual function of guiding the end of the latch into the slot 40 in the event that the leg has been moved upwardly to such an extent that the end of the latch is partially withdrawn from the slot, and that of providing clearance for the recess 43 which might engage any sharp edges or corners at the mouth of the slot and thereby prevent downward movement of the leg 27.

As the leg 27 moves from the horizontal to a generally vertical position, the recess 43 approaches the latch pin 42 and, after the leg moves slightly beyond an orientation of perpendicularity with the table top, seats the latch pin therein. This seating action is positive because of the biasing force exerted by the coil spring 49 which urges the latch and recess 43 therein toward such engagement. As mentioned before, the walls of the recess 43 snugly engage the pin 44 irrespective of any Wearing of the pin or walls of the recess, because of the taper that characterizes the recess and the dimensional relation thereof with the diameter of the latch pin.

The interlocking action of the latch bar 44 and pin 42 occurs after the leg 27 moves beyond center, or beyond a position of perpendicularity with the table top 11. Thus, even though the leg 27 is not manually moved into its locking position, the weight of the table will enforce such movement because in bearing downwardly thereon, it forces the leg outwardly and into the locking position thereof. It may be noted that gaming tables, banquet tables, etc., are generally located in rooms having smooth, uncovered floors so that the lower end of the leg can slide thereon, and thus facilitate its movement into the locking position. Further, the lower end of the leg may be equipped with a foot or automatic leveling device which may further facilitate sliding movemen thereof with respect to the underlying floor. When the leg is in its locking position, the upper edge thereof adjacent the inclined walls 52 and 53 at the mouth of the slot 40, abuts the undersurface of the table top 11 and thus augments the interlock between the latch 44 and pin 42 in rigidly constraining the leg with respect to the table top.

When it is desired to collapse the leg 27, the latch 44 is grasped and pushed upwardly to remove the recess 43 from about the latch pin 42; and the leg in thus being freed may be swung upwardly into adjacency with the undersurface of the table top. Such movement of the leg will force the latch 44 to pivot in a counterclockwise direction about the pivot axis 45 thereof, whereupon it approaches the depending walls 19 and 20 of the bracket sections 17 and 18. This could be dangerous if the fingers were interposed therebetween; and for that reason, the recessed areas 54 are provided in such depending walls to thus prevent pinching of the fingers as the latch rotates upwardly. It will be noted that the coil spring 49 is seated or anchored on the flange end 48 of the latch bar at the corner thereof adjacent the tail 24 of the bracket section 18. Thus, the longitudinal axis of the spring extends in parallelism with the 24 which, in turn, is parallel to the plane defined aeealse by the latch 44. Consequently, no unnecessary lateral torque is applied to the latch, and it therefore moves smoothly and freely through the slot 40.

Although the leg 27 is made from relatively thin sheet metal stock, it is nevertheless strong because of the angular configuration thereof, supplemented by the rounded edges 35 and 36 which are substantially cylindrical. Furthermore, the wall 37 constrains the walls 32 and 34 against both tensile and compression forces imposed thereacross. It should also be noted that since the upper edge of the leg 27 abuts the undersurface of the table top 11, when the leg is in its supporting position, the weight of the table is imposed directly onto the leg and is not transferred thereto through the bracket 15 and pins 30 and 31 which pivotally connect the leg thereto. Consequently, these pivotal pins need not be exceptionally strong.

The plate 41 reinforces the planar wall 33 of the leg at the point of force application thereto through the latch 44. The reinforcing wall 37 also functions as a safety stop in that it can be abutted by the lug 47 and adjacent edge of the latch 44, in the event that the leg in some manner could be moved beyond its extended support position wherein the latch interlockingly engages the latch pin 42, and the upper edges of the leg are contiguous with the table top.

While in the foregoing specification an embodiment of the invention has been set forth in considerable detail for purposes of amply disclosing the same, it will be apparent to those skilled in the art that numerous changes may be made in those details without departing from the spirit and principles of the invention.

We claim:

1. A folding leg mechanism for use with tables and equipment having folding \legs, a bracket fixedly secured to such table along the underside thereof and being provided with spaced arms, a leg having a U-shaped outer shell of sheet metal and an inner cross-bracing shell secured marginally thereto, said leg being pivotally mounted through the sides of the outer shell adjacent an end thereof to said arms for pivotal movement through an angle in excess of 90 from a generally horizontal folded posii011} parallel with said bracket to a generally over-thecenter inclined support position, said leg having an elongated slot extending longitudinally along the outer shell through to the pivotally mounted end thereof, a latch pin extending across said slot near the closed end thereof, a latch pivotally supported intermediate the ends thereof by said bracket in alignment with said slot for longitudinal movement therethrough and having a tapered recess of a minimum width less than the thickness of said pin for receiving said latch pin in self-tightening relationship when said leg is in said support position, said recess opening generally at right angles to said latch, and spring means connecting said bracket to said latch at the end thereof remote from said tapered recess for biasing the recessed portion of the latch toward said latch pin, said latch pin and said recess being automatically engaged to establish an interlock therebetween when said leg in the unfolding thereof is moved slightly beyond a position of perpendicularity with such table.

2. The folding leg mechanism of claim 1 in which the latch has an element slidable along the back side of said outer shell adjacent said slot and said spring means comprises a helical spring disposed approximately parallel with said latch when the leg is folded against the table and a generally angle of increasing leverage with said latch when the leg is extended and latched, said spring imparting to said latch a rotational force which is transmitted to the leg and increases as the angle between said latch and said spring increases to said generally 45 angle.

3. The combination called for in claim 1 wherein said arms are spaced widely where the leg is pivotally supported therebetween and are closely spaced where the latch is pivotally mounted, said arms being rigidly seourable to the underside of such table with the closely spaced arms oriented at the corner of the table, said closely spaced arms being cut away to provide clearance for the said portion of said latch.

4. The structure of claim 1 with said leg having a generally planar front wall in the outer shell and side walls diverge outwardly therefrom with a reinforcing Wall of the inner shell extending between said diverging walls in a generally parallel relation with said planar front wall with the outer edges of the outer shell beaded around the edges of the inner shell and the two beaded edges taper downwardly.

References Cited in the file of this patent UNITED STATES PATENTS 1,529,482 Hall Mar. 10, 1925 2,432,266 Wilkinson Dec. 9, 1947 2,708,145 Anderson et al. May 10, 1955 

